Best way to backup your partition?

Question

What is the best way to back up a partition? /dev/sda1 is windows and sda2 is Archlinux. Say if I wanted to reformat sda2 with an new filesystem, but continue to use the exact same installation of Archlinux that I've tailored everywhere possible (I would have to change fstab of course), what would be the best way to backup all files with compression while keeping ownerships and rights? (note: speed is favoured over high compression here though, but any compression would be nice)
All advices are welcome

Answer 1

Fackamato,
I regularly backup using 'rsync'. It has the advantage of only copying changed/new files, eventually deleting deleted
ones.
You can use a mounted NAS, or an internal partition as target. If the NAS also has 'rsync', you can also use it in client/server mode.
F.e., on a local internal partition:
rsync -av --delete --delete-excluded --exclude="/sys/**" --exclude="/proc/** " --exclude="/backup/" / /backup
/backup being a mounted backup partition
'rsync' is most useful if you regularly backup, but has some interest also in one shot copies: if for some reason
the copy fails, f. e. out of space, when you solve the problem and restart, it will only copy what it needs to.
For your particular case, if you have a spare internal partition with enough space (or make one fiddling with gparted),
you could:
mount /dev/sda3 /backup (sda3 being your new partition)
rsync -av --delete --delete-excluded --exclude="/sys/**" --exclude="/proc/** " --exclude="/backup/" / /backup
Change /etc/fstab on sda3.
Add the necessary lines to menu.lst (I suppose you are using Grub) to boot from sda3.
So you can test that everything works before destroying sda2.
Mektub